Nucleotides such as ATP and GTP play a pivotal role in many biological activities. Nucleotide-cation interactions are essential for the stabilization, function and regulation of nucleotides. The specific and often highly selective interactions of nucleotides with the proteins are required to perform their biological functions. This proposal aims at characterizing the interactions of nucleotides with cations and proteins by NMR spectroscopy. The specific aims of the proposed research are to investigate: (1) the interactions of nucleotides with cations;(2) the mechanisms involved in the interactions of ATP/ADP with myosin and actin;and (3) the binding of ATP/GTP to bovine serum albumin (BSA) or ubiquitin. The studies involve NMR chemical shifts, T1, T2 relaxation and diffusion measurements. The NMR data will provide valuable information: a) to assess the stability of nucleotides;b) on the mechanisms of GTP/ATP hydrolysis;c) to evaluate the interplay of nucleotide-myosin/actin interactions in the ATP-driven cyclic associationdissociation of actin-myosin;and d) to verify whether BSA and ubiquitin are the candidates as ATPase or GTPase to induce ATP or GTP hydrolysis. These NMR studies have significance in biological and biomedical sciences. The successful studies conducted by the PI for his MBRS-SCORE Program Pilot- Project (2001-2005) using NMR facility at Savannah State Univeristy formed the basis for the proposed research. If funded, this SCORE research project would enable the PI not only to continue his already establshied research involving NMR studies but also train students from the MARC U*STAR and NSFHBCU- UP Programs. The results from this study will be used for presenting at national and international conferences, for publication in peer-reviewed journals and for seeking extramural funding to continue the research beyond the MBRS-SCORE Program period.